diff --git a/Directory.Build.props b/Directory.Build.props
index f03de8c..9da913d 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -10,4 +10,14 @@
     <Deterministic>true</Deterministic>
   </PropertyGroup>
 
+  <!-- Single version source. Local builds are 0.1.0-dev; release builds pass an
+       explicit -p:Version=<tag-version>, which overrides both parts. The SDK's
+       built-in SourceLink appends the git commit as "+<sha>" build metadata on
+       AssemblyInformationalVersion, which the About dialog and the CLI's
+       version output surface as the short hash. -->
+  <PropertyGroup>
+    <VersionPrefix>0.1.0</VersionPrefix>
+    <VersionSuffix>dev</VersionSuffix>
+  </PropertyGroup>
+
 </Project>
diff --git a/docs/CLI.md b/docs/CLI.md
index 666db8f..da5288f 100644
--- a/docs/CLI.md
+++ b/docs/CLI.md
@@ -234,5 +234,5 @@ done
 
 ```console
 $ gclo --version
-0.1.0
+0.1.0-beta.6 (9ac6c2bde)
 ```
diff --git a/gclo.Cli/Program.cs b/gclo.Cli/Program.cs
index fe55bc0..9a8c6e9 100644
--- a/gclo.Cli/Program.cs
+++ b/gclo.Cli/Program.cs
@@ -1,4 +1,4 @@
-using System.Reflection;
+using gclo.Engine;
 
 namespace gclo.Cli;
 
@@ -102,16 +102,7 @@ internal static class Program
     }
 
     private static string Version()
-    {
-        Assembly assembly = typeof(Program).Assembly;
-        string version =
-            assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion
-            ?? assembly.GetName().Version?.ToString()
-            ?? "unknown";
-
-        // Strip the '+<metadata>' suffix (e.g. a SourceLink commit hash); it is
-        // noise for a scripted version check.
-        int plus = version.IndexOf('+');
-        return plus >= 0 ? version[..plus] : version;
-    }
+        // Shared with the GUI's About dialog: "0.1.0-beta.6 (9ac6c2b)" for
+        // releases, "0.1.0-dev (<hash>)" for local builds.
+        => BuildVersion.Describe(typeof(Program).Assembly);
 }
diff --git a/gclo.Cli/gclo.Cli.csproj b/gclo.Cli/gclo.Cli.csproj
index 31b9fc5..245e19d 100644
--- a/gclo.Cli/gclo.Cli.csproj
+++ b/gclo.Cli/gclo.Cli.csproj
@@ -8,7 +8,6 @@
     <AssemblyName>gclo</AssemblyName>
     <RootNamespace>gclo.Cli</RootNamespace>
     <InvariantGlobalization>true</InvariantGlobalization>
-    <Version>0.1.0</Version>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/gclo.Engine.Tests/BuildVersionTests.cs b/gclo.Engine.Tests/BuildVersionTests.cs
new file mode 100644
index 0000000..c6a846b
--- /dev/null
+++ b/gclo.Engine.Tests/BuildVersionTests.cs
@@ -0,0 +1,30 @@
+using gclo.Engine;
+
+namespace gclo.Engine.Tests;
+
+/// <summary>Formatting of the version + git-hash build identity string.</summary>
+public sealed class BuildVersionTests
+{
+    [Theory]
+    [InlineData(null, "unknown")]
+    [InlineData("", "unknown")]
+    [InlineData("   ", "unknown")]
+    [InlineData("1.2.3", "1.2.3")]
+    [InlineData("0.1.0-dev", "0.1.0-dev")]
+    [InlineData("0.1.0-beta.6+9ac6c2b1234567890abcdef", "0.1.0-beta.6 (9ac6c2b12)")]
+    [InlineData("1.2.3+abc", "1.2.3 (abc)")]
+    [InlineData("1.2.3+9ac6c2b1234567890.dirty", "1.2.3 (9ac6c2b12)")]
+    [InlineData("1.2.3+", "1.2.3")]
+    public void Format_ProducesReadableIdentity(string? informational, string expected)
+    {
+        Assert.Equal(expected, BuildVersion.Format(informational));
+    }
+
+    [Fact]
+    public void Describe_UsesThisAssembly_AndNeverThrows()
+    {
+        string described = BuildVersion.Describe(typeof(BuildVersionTests).Assembly);
+
+        Assert.False(string.IsNullOrWhiteSpace(described));
+    }
+}
diff --git a/gclo.Engine/BuildVersion.cs b/gclo.Engine/BuildVersion.cs
new file mode 100644
index 0000000..71fb03f
--- /dev/null
+++ b/gclo.Engine/BuildVersion.cs
@@ -0,0 +1,49 @@
+using System.Reflection;
+
+namespace gclo.Engine;
+
+/// <summary>
+/// Human-readable build identity shared by the app's About dialog and the CLI's
+/// version output: the semantic version plus the short git commit the build came
+/// from, e.g. "0.1.0-beta.6 (9ac6c2b)" for releases or "0.1.0-dev (3a87f9e)" for
+/// local builds.
+/// </summary>
+public static class BuildVersion
+{
+    private const int ShortHashLength = 9;
+
+    /// <summary>Describes <paramref name="assembly"/>'s version and commit.</summary>
+    public static string Describe(Assembly assembly)
+        => Format(assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion
+            ?? assembly.GetName().Version?.ToString());
+
+    /// <summary>
+    /// Formats an informational version: the "+&lt;metadata&gt;" suffix that SourceLink
+    /// appends becomes a parenthesized short commit hash.
+    /// </summary>
+    public static string Format(string? informationalVersion)
+    {
+        if (string.IsNullOrWhiteSpace(informationalVersion))
+        {
+            return "unknown";
+        }
+
+        int plus = informationalVersion.IndexOf('+');
+        if (plus < 0)
+        {
+            return informationalVersion;
+        }
+
+        string version = informationalVersion[..plus];
+        string metadata = informationalVersion[(plus + 1)..];
+        // Metadata may carry more than the sha (dot-separated); the hash is first.
+        int dot = metadata.IndexOf('.');
+        string hash = dot >= 0 ? metadata[..dot] : metadata;
+        if (hash.Length > ShortHashLength)
+        {
+            hash = hash[..ShortHashLength];
+        }
+
+        return hash.Length == 0 ? version : $"{version} ({hash})";
+    }
+}
diff --git a/gclo/AboutDialog.xaml.cs b/gclo/AboutDialog.xaml.cs
index 08173c9..113c75c 100644
--- a/gclo/AboutDialog.xaml.cs
+++ b/gclo/AboutDialog.xaml.cs
@@ -18,29 +18,13 @@ namespace gclo
         }
 
         /// <summary>
-        /// Returns the app version formatted as "major.minor.build". Prefers the MSIX
-        /// package version; Package.Current throws when the app runs unpackaged
-        /// (no package identity), in which case the assembly version is used instead.
+        /// Returns the build identity synced to the release pipeline: the semantic
+        /// version CI injects for the tag (0.1.0-dev on local builds) plus the short
+        /// git commit, e.g. "0.1.0-beta.6 (9ac6c2b)". The MSIX package version is
+        /// deliberately not used — its numeric quad cannot carry prerelease tags or
+        /// commit hashes, so it cannot distinguish a local build from a release.
         /// </summary>
         private static string GetAppVersion()
-        {
-            try
-            {
-                var packageVersion = Windows.ApplicationModel.Package.Current.Id.Version;
-                return $"{packageVersion.Major}.{packageVersion.Minor}.{packageVersion.Build}";
-            }
-            catch (Exception)
-            {
-                Version? assemblyVersion = Assembly.GetExecutingAssembly().GetName().Version;
-                if (assemblyVersion is null)
-                {
-                    return "1.0.0";
-                }
-
-                // Version.Build is -1 when the assembly version has fewer than three parts.
-                int build = assemblyVersion.Build < 0 ? 0 : assemblyVersion.Build;
-                return $"{assemblyVersion.Major}.{assemblyVersion.Minor}.{build}";
-            }
-        }
+            => gclo.Engine.BuildVersion.Describe(Assembly.GetExecutingAssembly());
     }
 }